Employing different signal thresholds based on type of information transmitted

ABSTRACT

A method is disclosed for determining whether to transmit from a first unit to a second unit, where the transmission is one of a first type and a second type. In the method, a signal from the second unit is received at the first unit, and the strength of the signal as received at the first unit is measured. A determination is made of whether the transmission is of the first type or the second type, and a first threshold is selected if the transmission is of the first type, or else a second threshold is selected if the transmission is of the second type. The measured signal strength is then compared to the selected threshold, and the transmission proceeds only if the measured signal strength exceeds the selected threshold.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application is a continuation of U.S. patentapplication Ser. No. 09/563,872, file May 3, 2000, entitled “EmployingDifferent Signal Thresholds Based On Type of Information Transmitted”,and issued as U.S. Pat. No. 6,______ on ______, 2003, herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to a method for transmittinginformation from a transmission site to a receiving unit. Moreparticularly, the present invention relates to such a method fordeciding whether to transmit the information, wherein the receiving unitis a two-way unit that sends a signal to the site, and wherein thedecision to transmit is based on a comparison of the strength of thesignal as received at the site against a signal threshold that differsbased on the type of information that is to be transmitted.

BACKGROUND OF THE INVENTION

[0003] In many transmission systems, a decision on whether to transmitinformation from a transmission site to a receiving unit is made basedon whether the receiving unit will likely actually receive theinformation to be transmitted. In at least some of such transmissionsystems, the receiving unit is a two-way unit that can receive the senttransmission from the transmission site and that can also send signalsback to the transmission site.

[0004] In such transmission systems, one way of deciding whether totransmit the information is to have the receiving unit send a signal tothe transmission site, to then examine the strength of such sent signalas received at the transmission site, and to then make a judgment of theability of the receiving unit to receive the transmitted informationbased on such signal strength. That is, the ability of the receivingunit to receive the transmitted information from the transmission sitemay be related, at least roughly, to the strength of a sent signal asreceived from such receiving unit at such transmission site. Moreparticularly, if the signal strength is relatively strong, it is verylikely that the receiving unit can receive the transmitted information.Correspondingly, if the signal strength is relatively weak, it is verylikely that the receiving unit cannot receive the transmittedinformation.

[0005] One transmission system where such a decision is made is acellular telephone system. In such a cellular telephone system, amobile/cellular phone is a radio transceiver that is coupled to acellular switch by way of a particular cellular tower that is also aradio transceiver, and the phone and the tower transmit to and receivefrom each other over pre-defined radio frequencies.

[0006] In such cellular telephone system, for example, a decision ismade whether voice communications can commence between the tower and thephone based on the strength of a signal sent from the phone and receivedat the tower. Such signal strength as received at the tower, typicallyexpressed in terms of decibels, is compared to a pre-defined signalstrength threshold, also typically expressed in decibels, to determinewhether the aforementioned voice communications can commence. Moreparticularly, if the signal strength is stronger than the threshold, itis very likely that the phone can receive the voice communications fromthe tower, and communications may commence. Correspondingly, if thesignal strength is weaker than the threshold, it is very likely that thephone cannot receive the voice communications from the tower, andcommunications may not commence.

[0007] As may be appreciated, the aforementioned cellular telephonesystem is expanding to include many additional services over and abovemere voice communications. In particular, one additional service is datacommunications, wherein textual/ASCII messages are delivered to aparticular cellular telephone for display on a display associated withsuch cellular phone. The display may be any appropriate display, but istypically a pixelated display such as an LCD screen on the surface ofthe cellular phone. Thus, a message is composed and sent from anappropriate source, is transmitted to the cellular phone by way of thecellular telephone system, and is then displayed by the cellular phoneon the display associated therewith.

[0008] As with the decision on whether voice communications cancommence, the decision on whether to transmit the message data from thetower to the phone is made based on the strength of a signal sent fromthe phone and received at the tower. More particularly, if the signalstrength is above a pre-defined threshold, it is very likely that thephone can receive the message data from the tower, and transmissionthereof may commence. Correspondingly, if the signal strength is belowthe pre-defined threshold, it is very likely that the phone cannotreceive the message data from the tower, and transmission thereof maynot commence.

[0009] An issue arises in that a typical cellular phone can reliablyreceive message data even under conditions where voice communicationsare inadvisable. That is, conditions may exist (1) where both voicecommunications and message data reception are advisable, (2) where onlymessage data reception is advisable, or (3) where neither voicecommunications nor message data reception is advisable. Nevertheless,when determining whether voice communications can commence and also whendetermining whether message data transmission can commence, theaforementioned cellular system compares signal strength to only a singlepre-defined threshold, where such threshold is calibrated for voicecommunications. As a result, message data transmission does not occurunder condition (2), above, even though such message data transmissionis in fact advisable.

[0010] Accordingly, a need exists for a method for deciding whether totransmit message data and for deciding whether voice communications cancommence, wherein such decision is based at least in part on onethreshold for message data transmission and another threshold for voicecommunications.

SUMMARY OF THE INVENTION

[0011] The present invention satisfies the aforementioned need byproviding a method for determining whether to transmit from a first unitto a second unit, where the transmission is one of a first type and asecond type. In the method, a signal from the second unit is received atthe first unit, and the strength of the signal as received at the firstunit is measured. A determination is made of whether the transmission isof the first type or the second type, and a first threshold is selectedif the transmission is of the first type, or else a second threshold isselected if the transmission is of the second type. The measured signalstrength is then compared to the selected threshold, and thetransmission proceeds only if the measured signal strength exceeds theselected threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The foregoing summary as well as the following detaileddescription of the present invention will be better understood when readin conjunction with the appended drawings. For the purpose of theillustrating the invention, there are shown in the drawings embodimentswhich are presently preferred. As should be understood, however, theinvention is not limited to the precise arrangements andinstrumentalities shown. In the drawings:

[0013]FIG. 1 is a diagrammatic view and shows a typical cellulartelephone system such as that which would employ the method of thepresent invention; and

[0014]FIG. 2 is a flow chart showing steps performed in selecting athreshold in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0015] Certain terminology may be used in the following description forconvenience only and is not considered to be limiting. For example, thewords “left”, “right”, “upper”, and “lower” designate directions in thedrawings to which reference is made. Likewise, the words “inwardly” and“outwardly” are directions toward and away from, respectively, thegeometric center of the referenced object. The terminology includes thewords above specifically mentioned, derivatives thereof, and words ofsimilar import.

[0016] Referring to the drawings in detail, wherein like numerals areused to indicate like elements throughout, there is shown in FIG. 1 atypical cellular telephone system 10 in accordance with one embodimentof the present invention. As seen, the system 10 includes one or moremobile switching centers 12, one or more radio transceiver cellulartowers 14, and one or more cellular telephones 16. As is known, eachtower 14 is associated with a particular switching center 12, and,depending on the location of a particular telephone 16, such phone 16registers to one of the towers 14 and therefore is switched through theassociated switching center 12. Thus, voice communication between thephone 16 and the rest of the world is achieved through the registeredtower 14 and the associated switching center 12, and data transmissionthat originates from the world for the phone 16 is routed to theassociated switching center 12 for further transmission to theregistered tower 14 and then to the phone 16.

[0017] Note that each tower 14 need not necessarily be an actual tower.Instead, the functional elements of a tower 14 may reside on the top orside of a building, on a mountain or mountainside, or in any otherappropriate location, all without departing from the spirit and scope ofthe present invention. Such functional elements may even be positionedon the ground or on a floating platform at sea, if appropriate asdictated by circumstances and terrain, for example.

[0018] Such a cellular telephone system 10 is generally known to therelevant public, and therefore need not be described in any greaterdetail except to the extent so indicated below. Although the presentinvention as disclosed herein is described in terms of such a cellulartelephone system 10, it is to be recognized that the present inventionmay also be employed in connection with other systems without departingfrom the spirit and scope of the present invention. For example, suchother system may be any wireless or wired system, any audio, video,and/or data transmission system, etc.

[0019] Typically, and as seen in FIG. 2, when a phone 16 is firstpowered on (step 201), the phone 16 scans for acceptable controlchannels 18 as transmitted from the towers 14 (step 203), and thenselects one of the acceptable control channels (step 205). As may beappreciated, each tower 14 transmits at least one control channel 18,and each acceptable control channel 18 may have a minimum signalstrength, for example. Likewise, the selected control channel 18 may bethe strongest one of the acceptable control channels 18 detected by thephone 16, thus indicating that the corresponding tower 14 is closest tothe phone 16. Of course, other bases may be employed for selecting anacceptable control channel 18 without departing from the spirit andscope of the present invention.

[0020] As may also be appreciated, the selected control channel 18includes information readable by the phone 16, including but not limitedto frequency information for transmitting to and receiving from thecorresponding tower 14. Thus, the phone 16 reads such controlinformation from the control channel 18 (step 207) and uses such controlinformation to contact and register with the corresponding tower 14 andassociated switching center 12 (step 209). Thus, the world can contactthe phone 16 and the phone 16 can also contact the world through suchtower 14 and switching center 12.

[0021] In the present invention, the switching center 12 may decide tocontact the phone 16 by way of the tower because such switching center12 is attempting to establish voice communications between such phone 16and a calling party, because such switching center 12 is attempting tosend message data from a message source to the phone 16, because suchswitching center 12 is attempting to perform another type ofcommunication with the phone 16, or because of another reason.Accordingly, the switching center 12 sends a page to the phone by way ofthe tower 14 (step 211). As is to be appreciated, such page is sent overa frequency as set forth by the control information on the controlchannel 18, and the phone 16 is expected to be monitoring such frequencyif in fact such phone 16 is still powered on, still within range of thetower 14, and still registered to such tower 14. The phone 16, uponreceiving the page (step 213), transmits an acknowledgment of the pageto the switching center 12 by way of the tower 14 (step 215). Similar tothe page, such acknowledgment is sent over a frequency as set forth bythe control information on the control channel 18, and the tower 14 isexpected to be monitoring such frequency for such acknowledgment.

[0022] When such acknowledgment is received at the tower 14 (step 217),the strength of the acknowledgment signal as received at the tower 14 ismeasured (step 219). Such strength is typically measured in decibels,although other measurement parameters/units may also be employed withoutdeparting from the spirit and scope of the present invention. As wasdiscussed above, once measured, the signal strength is then examined inorder to make a judgment of the ability of the phone 16 to commencevoice communications or receive message data based on such signalstrength. That is, the ability of the phone 16 to receive the messagedata or commence voice communications may be related, at least roughly,to the signal strength of the acknowledgment as received from such phone16 at such tower 14. As was pointed out above, such signal strength mustbe above a minimum threshold value.

[0023] As was also pointed out above, a typical cellular phone 16 canreliably receive message data even under conditions where voicecommunications are inadvisable. That is, conditions may exist (1) whereboth voice communications and message data reception are advisable, (2)where only message data reception is advisable, or (3) where neithervoice communications nor message data reception is advisable. This isparticularly true when the message data is simple digitized ASCII dataor the like, although other types of message data may be employedwithout departing from the spirit and scope of the present invention.However, when determining whether voice communications can commence andalso when determining whether message data transmission can commence,previous comparisons of signal strength were performed with regard toonly a single pre-defined threshold calibrated for voice communications.As a result, message data transmission did not occur under condition (2)even though such message data transmission was in fact advisable.

[0024] Accordingly, in one embodiment of the present invention, thedetermination of whether voice communications can commence is made withregard to a voice threshold, and the determination of whether messagedata transmission can commence is done with regard to a messagethreshold different from the voice threshold. The voice threshold anddata threshold may be any appropriate thresholds without departing fromthe spirit and scope of the present invention, although it is expectedthat the voice threshold will be higher than the data threshold. As aresult, message data transmission does in fact occur under condition (2)even though voice communication is not advisable. In one embodiment ofthe present invention, the voice threshold is about −95 to −90 dBm,while the data threshold is about −105 to −103 dBm.

[0025] In particular, and still referring to FIG. 2, the examination ofthe measured signal strength of the acknowledgment signal begins with adetermination of whether voice communications is to commence or messagedata transmission is to commence (step 221). As should be appreciated,the switching center 12 already possesses such information inasmuch asthe switching center 12 originally sent the page to the phone 16 by wayof the tower 14 (step 211) because it had a voice communication or datatransmission for such phone 16.

[0026] Once the determination of voice communication or datatransmission has been made, an appropriate signal threshold is selected(step 223 a, 223 b). As should be appreciated, in the case of a voicecommunication, the voice threshold is obtained, and in the case of adata transmission, the data threshold is obtained. Thereafter, thesignal strength of the acknowledgement signal from the phone 14 asobtained at the tower 14 is compared to the selected voice threshold ordata threshold (step 225), and voice communication or data transmission,as the case may be, is allowed to commence only if the signal strengthexceeds the selected threshold (step 227).

[0027] Note that, with regard to the message data transmitted, anyappropriate data transmission protocol may be employed without departingfrom the spirit and scope of the present invention. For example, in oneembodiment of the present invention, the SMS (Short Message Service)protocol is employed. Such SMS protocol is defined within the GSM(Global System for Mobile Communications) digital mobile phone standard.As was mentioned above, the transmitted data, once received by the phone16, is then displayed on a display 20 associated with such phone 16. Thedisplay 16 may be any appropriate display, but is typically a pixelateddisplay such as an LCD screen on the surface of the phone 16. Thus, amessage is composed and sent from an appropriate source, is transmittedto the phone 16 by way of the cellular telephone system 10, and is thendisplayed by the phone 16 on the display 20 associated therewith. Thedetails of such message composure, transmission, reception, and displayare generally know to the relevant public, and therefore need not bedescribed in any greater detail.

[0028] As should be understood, the method of transmitting informationand choosing a threshold as embodied in the present invention may beemployed by the switching center 12 or by another element withoutdeparting from the spirit and scope of the present invention. Moreover,although the method has been heretofore described in terms of onethreshold for voice communications and another threshold for messagedata transmission, it is to be recognized that additional thresholds maybe employed for other types of communications.

[0029] Although not necessary, such method is likely embodied in theform of computer programming that is automatically run. Such programmingis relatively straightforward and should be apparent to the relevantpublic, and therefore need not be described herein in any detail.Accordingly, any particular form of programming and programming languagemay be employed without departing from the spirit and scope of thepresent invention.

[0030] In the foregoing description, it can be seen that the presentinvention comprises a new and useful method for deciding whether totransmit message data and for deciding whether voice communications cancommence, wherein such decision is based at least in part on onethreshold for message data transmission and another threshold for voicecommunications. It should be appreciated that changes could be made tothe embodiments described above without departing from the inventiveconcepts thereof. It should be understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims.

1. A method for determining whether to transmit from a mobile unit to afixed unit, the transmission being one of a first type and a secondtype, the method comprising: receiving a signal from the fixed unit atthe mobile unit; measuring the strength of the signal as received at themobile unit; determining whether the transmission is of the first typeor the second type; selecting a first threshold if the transmission isof the first type; selecting a second threshold if the transmission isof the second type; comparing the measured signal strength to theselected threshold; and proceeding with the transmission only if themeasured signal strength exceeds the selected threshold.
 2. The methodof claim 1 wherein the transmission is one of a voice communication andmessage data transmission, the method comprising: determining whetherthe transmission is a voice communication or a message datatransmission; selecting a voice threshold if the transmission is a voicecommunication; and selecting a data threshold if the transmission is amessage data transmission.
 3. The method of claim 2 comprising:selecting a voice threshold if the transmission is a voicecommunication; and selecting a data threshold lower than the voicethreshold if the transmission is a message data transmission.
 4. Themethod of claim 1 wherein the transmission is one of a first type, asecond type, or a third type, the method comprising: determining whetherthe transmission is of the first type, the second type, or the thirdtype; selecting a first threshold if the transmission is of the firsttype; selecting a second threshold if the transmission is of the secondtype; and selecting a third threshold if the transmission is of thethird type.
 5. The method of claim 1 for determining whether to transmitfrom a portable radio transceiver to a radio tower, the methodcomprising: receiving a signal from the radio tower at the portableradio transceiver; and measuring the strength of the signal as receivedat the portable radio transceiver.
 6. The method of claim 5 fordetermining whether to transmit from a cellular telephone to a cellulartelephone system tower, the method comprising: receiving a signal fromthe tower at the telephone; and measuring the strength of the signal asreceived at the telephone.
 7. The method of claim 1 further comprisingsending a page from the mobile unit to the fixed unit, wherein receivinga signal from the fixed unit at the mobile unit comprises receiving anacknowledgment of the page at the mobile unit.